Operator`s manual

OPERATION
329
ANTI-LOCK BRAKING SYSTEM (ABS)
The vehicle has a standard brake system, equipped with an electronic
speed monitoring and control system, Anti-lock Braking System (ABS).
ABS monitors wheel speed continuously but is not involved in
controlling the wheel speed unless there is an emergency. In normal
braking applications, the standard air brake system is in effect.
For proper ABS operation, DO NOT change tire
sizes. The size of the tires installed during
production are programmed into the electronic
control unit. Installing different sized tires could
result in a reduced brake force, leading to longer
stopping distances or accidents.
There is a sensor installed in each wheel on a monitored axle. The
sensors transmit information to the electronic control unit (ECU). The
ECU interprets the signals and calculates wheel speed, wheel
retarding and a vehicle reference speed. If the calculations indicate a
wheel lock-up situation, a signal is sent from the ECU to the
appropriate ABS modulator valve to reduce braking pressure. During
emergency braking, the modulator valve alternately reduces, increases
or maintains air pressure in the brake chamber to prevent wheel
lock-up.
During emergency or reduced-traction stops, fully depress the foot
brake pedal until the vehicle comes to a safe stop. DO NOT PUMP the
brake pedal. With the brake pedal fully depressed, the ABS will control
all wheels to provide steering control and a reduced braking distance.
Although the ABS improves vehicle control during emergency braking
situations, the operator still has the responsibility to change driving
styles depending on the existing traffic, road and/or weather conditions.
For example, the ABS cannot prevent an accident if the driver is
speeding or following too closely on slippery surfaces.
vn-vhd.bk Page 329 Tuesday, July 1, 2008 9:44 AM